Lubricant compositions



Patented Dec. 2, 19522 UNITED STATES 2,620,309 PATENT OFFICE niaResearch Corporation,

San Francisco,

Calif., a corporation of Delaware No Drawing. Application December 16,1950, Serial No. 201,254

13 Claims.

The present invention relates to the preparation of novel and usefullubricatin oil compositions. More particularly, the invention has to dowith the preparation of lubricating oil compositions comprising mineraloil, polyalkylene glycol polymeric material, and a specified polarliquid compound, whereby the miscibility characteristics of mineral oiland polyoxyalkylene polymeric material are substantially improved.

Polyalkylene glycol polymeric mixtures having the structuralconfiguration LO JQ wherein n is an integer greater than one and thefree valences may be satisfied with hydrogen atoms and/or organicradicals, such as methyl, ethyl, propyl radicals, etc., have hithertobeen proposed as synthetic lubricants. These materials may be preparedfrom ethylene oxide, and the higher 1,2-epoxides, such as 1,2-propy1eneoxide, the butylene oxides, mixtures of these materials, and thecorresponding glycols. As known in the art, the resulting products maybe polyoxyallrylene diols or polyalkylene glycol derivatives, in whichone or both of the terminal hydroxyl groups have been removed during thepolymerization reaction or subsequently thereto, as by etherification oresterification to yield monoor di-ether or monoor di-ester groups or acombination of such terminal groups whereby certain desirable propertiesare imparted to the final polymeric mixture.

By way of illustration, U. S. Patent No. 2,448,664 describes thepreparation of a polyoxypropylene polymeric mixture according to' theequation ROH (OC H:;CH3) R.(OC;EI3.CH3)OH Mcnoliydric 1,2-propylencPol-yoxypropylene alcohol oxide monohydroxy compound These products havemolecular weights ranging from about 400 to 2,000 and higher, and arealleged to be useful as synthetic lubricants.

More recently polyoxyalkylene polymeric and copolymeric mixturescontaining polymer units having more than two carbon atoms separatingoxygen atoms in the polymer chain have been prepared and described. Forexample, U. S. Patent No. 2,520,733 describes the preparation ofpolymers and copolymers derived-from trimethylene glycol.

The foregoing compounds, as well as additional polymeric materialscontemplated by the invention, are further described in U. S. Patent No.2391, 132.

As compared with mineral oils, the polyalkylene glycols possess certainsuperior properties, as a result of which they would be more extensivelyused but for their high cost. For example, the polyalkyleneglycols havehigher viscosity indices, and lower pour points' 'th an mineral oils ofcomparable viscosity. A'further additional property is that uponoxidation they tend to decompose into harmless volatile in a'terialsrather than to form complex insoluble en'- gine deposits, their use inengine lubricatingth'us resulting in greater engine cleanliness.

It is also known that in general additives conventionally employed incombination with-amineral oil to improve one'or more properties thereof,such as oxidation and corrosion inhibitorsdetergents, and the like, areoften without effect when combined with the polyalkylene lycol polymers.Another disadvantage of polyalkylene glycol polymer materials is theirlimitedsolubility in mineral oils. At relatively high temperatures,

blends of mineral oil and pol-yalkyleneglycol polymer show phaseseparation. v

Notwithstanding the poor miscibility characteristics of blends ofpolyalkylene glycol-polymeric material and mineral oil,-the blends arecapabl of manifesting the desirable properties of the polymers.Moreover, certain conventional mineral oil additives have been founddesirably to affect the polymer when incorporated inthe polymericmaterial in the presence of mineral oil. For a number of reasons,therefore-and for the further reason of economy, it is desirable'to formblends of mineral oil and polyalkylen'e glycol polymeric material havingimproved miscibility characteristics.

Now, in accordance with the invention, it'has been found that themiscibility characteristics of blends of mineral oil and polyalkyleneglycol polymeric material can be improved substantially by the bringingtogether of mineral oil and said polymeric material in the presence of aparticular polar compound. More specifically, it has been found that themiscibility temperature, more fully hereinafter described, of mixturesor blends of mineral oil and polya-lkylene glycol polymer can beconsiderably lowered by the incorporation in a blend or mixture of theaforesaid components of a small amount of a halide having at least threealiphatic carbon atoms in the molecule.

More particularly, the halide contemplate'cl' by the invention is onecontaining at'le'ast three aliphatic carbon atoms and only'on'e halogenatom, that is, a monohalide, and is free from polar substituents, suchas amino or nitro radicals. These polar radicals, by imparting greaterpolarity to the halidethan it already possesses by virtue of the halogenatom, adversely a-liect the halide in its function of solubilizirigpolymer and mineral oil. On the other hand, substantiallynonpolar-substituent groups, such as those which consist solely of theelements of hydrogen and carbon, for example, a benzene ring, may

appear on the halide.

The halogen atom, moreover, need not be directly attached to analiphatic carbon atom. In short, the halide can be an alkyl halide of atleast three carbon atoms; an alkaryl halide in which the alkyl group hasat least three carbon atoms; an alicyclic halide, and an arylalkylhalide in which the alkyl grouping is of at least three carbon atoms.Preferably employed, however, is an alkyl halide of the type defined.The halogen atoms can be chlorine, bromine or iodine.

In general, it may be stated that the greater the number of aliphaticcarbon atoms in the halide molecule the more pronounced the miscibilityeffects imparted to the mixture of mineral oil and polymer. Therefore,halides having as many as 18 or more carbon atoms in the molecule aresuitable in carrying out the invention. Since,

however, the presence of aromatic carbon contributes little or nosolubilizing effect to the halide molecule, the number of aromaticcarbon atoms is accordingly ignored in determining the number ofeffective carbon atoms in the halide.

Specific examples of suitable halides are n-propyl chloride, n-butylbromide, n-butyl chloride, tert.-amyl chloride, isoamyl chloride, laurylchloride tert. butyl chloride, phenylpropyl chloride, cyclohexylchloride, isoamyl p-benzene chloride, dimethyl hexyl bromide, n-octyliodide, n-dodecyl iodide.

It has been found that the amount of halide required to effect animprovement in the miscibility characteristics of polyalkylene glycolpolymer and mineral oil blends is substantially independent of theproportions of mineral oil and polymer within a range of about 20 toabout 80% by volume of either component. That is, either component canbe present in the composition in an amount of about one-fourth to aboutfourfold the amount by volume of the other component, although forpractical purposes an equal amount of either component is preferred. Ingeneral, the amount of solubilizing halide can vary from an amount ofabout 1% to about 10% by volume of the finished composition, an amountof about 2% to 5% being preferred. While greater amounts than about canbe employed, such amounts are not particularly desirable because theyadversely aifect the properties of the finished composition, such asviscosity index.

In order to obtain quantitative data on the eifectiveness of thesolubilizing agent to improve the miscibility of polymer and mineraloil, the following method and apparatus were employed: A double-walledtest tube, having an inside diameter of about 11 mm., an outsidediameter of about 12 mm., and being about 9 cm. long, is

provided with a cork stopper, and fitted with a thermometer. Sufficientsample is placed in the tube to cover the bulb of the thermometer (about2 cc.) after which the test tube with contents is placed in a suitablecooling bath, the contents of the tube being continuously stirred withthe thermometer. Phase separation is manifested by a sudden cloudformation, and the temperature at which the cloud appears is noted andrecorded as the miscibility temperature.

The following examples are given to illustrate compositions prepared inaccordance with the invention:

A mixture of polyalkylene glycol polymer material and mineral oil wasprepared by mixing equal parts, by volume, of the polymer and mineraloil. The polymer was prepared from 1,2- propylene oxide and2-ethylhexanol, and had a Miscibility Example Temperature,

. lauryl chloride .I cyclohcXyl chloride phenylpropyl chloride...

Example 10 A composition consisting of volume per cent of the polymerand 20 volume per cent of the oil employed in the examples tabulatedabove had a miscibility temperature of 19 F. Addition of 10% by volumeof the composition of isoamyl chloride resulted in a composition havinga miscibility temperature of 25 F.

On the other hand, 20 volume per cent of the same polymer and 80 volumeper cent of the same oil resulted in a composition having a miscibilitytemperature of 53 F. Addition of 10 volume per cent of isoamyl chloridelowered the miscibility temperature to 5 F.

Example 11 To equal proportions, by volume, of the polymer employed inobtaining the data tabulated above, and of a mineral oil having aviscosity of 60.6 SSU at 210 F., there was added 10 volume per cent oftert.-amyl chloride. The blend of mineral oil and polymer alone had amiscibility temperature of 123 F., Whereas the finished blend had amiscibility temperature of '72 F. The mineral oil in this example wasderived from a phenol, cresol and propane treated residium of anintermediate base crude to give a waxy raffinate. The raflinate wasdewaxed by means of methyl ethyl ketone. the dewaxed oil treated withclay and then fractionated to yield the finished o1 Example 12Polyalkylene glycol polymeric material was prepared from methanol and1,2-propylene oxide and subsequently esterified with acetic anhydride,the finished polymer having a viscosity of 40.0 SSU at 210 F. To thisthere was added an equal volume of the, spray oil having a viscosity of34.1 SSU at 210 F. This resulted in a composition having a miscibilitytemperature of 30 F. Addition of 10 volume per cent of isoamyl chlorideresulted in a composition having a miscibility temperature of 18 F.

Example 13 A composition consisting of 45 volume per cent of the oildescribed in the example immediately above and 45 volume per cent of the2-ethylhexanol initiated polymer employed in obtaining the tabulateddata, and 10 volume per cent of tert.-

butyl chloride had a miscibility temperature of 22 F. Polymer and oil inequal proportions without the alcohol had a miscibility temperature of 0F.

Example 14 cibility temperature of 8 F. Addition of 10 volume per centisoamyl chloride resulted in a finished composition having a miscibilitytemperature of 36 F.

Example A water-initiated polypropene oxide polymer having a viscosityof 62.0 SSU was blended with an equal amount of a spray oil having aviscosity of 36.6 SSU at 210 F. The miscibility temperature of the blendwas 120 F. Addition of 10% by volume of the blend of lauryl chlorideresulted in a composition having a miscibility temperature of 74 F.

Example 16 A polymer was prepared from stoichiometric proportions ofethylene oxide and isobutylene oxide, employing 2-butanol to initiatethe polymerization reaction, the polymer being subsequently esterifiedwith acetic anhydride to yield a product having a viscosity of 48.6 SSUat 210 F. Equal proportions of this polymer with the oil used in thetabulated examples gave a composition having a miscibility temperatureof 82 F. Addition of 10% by volume of the blend of lauryl chlorideresulted in a composition having a miscibility temperature of 38 F.

As indicated in the foregoing examples, the mineral oil can be anyhydrocarbon oil of lubricating oil viscosity. It can be a straightmineral oil or a distillate derived from paraffinic, naphthenio,asphaltic or mixed base crudes. Moreover, the oil may be one refined byconventional methods, such as solventor acid-treated oils or mixturesthereof. Also satisfactory for purposes of the present invention aresynthetic oils such as those derived from the polymerization of olefinsor the Fischer-Tropsch process. Various blended oils are alsocontemplated by the invention.

Obviously many modifications and variations of the invention ashereinbefore set forth may be made without departing from the spirit andscope thereof, and therefore only such limitations should be imposed asare indicated in the appended claims.

We claim:

1. Lubricating oil composition comprising a major proportion of a blendof hydrocarbon oil and polyalkylene glycol polymeric material oflubricating oil viscosity in an amount, by volume, of about one-fourthto about four-fold the amount of said hydrocarbon oil, and a minoramount, suflicient substantially to lower the miscibility temperature ofsaid blend, of at least one monohalide having at least three aliphaticcarbon atoms, said monohalide being selected from the group consistingof alkyl, alkaryl, arylalkyl and alioyclic monohalides, said monohalidebeing free of polar substituents, and being soluble in said blend at themiscibility temperature of said blend.

2. Composition substantially as described in claim 1, wherein thehydrocarbon oil is a mineral oil.

3. Composition substantially as described in claim 2, wherein thepolyalkylene glycol polymeric material is a 1,2-polyalkylene glycolpolymeric material and has at least one terminal group selected from thegroup consisting of ether and ester groups.

4. Composition substantially as described in claim 2, wherein themonohalide is a chloride.

5. Composition substantially as described in claim 4, wherein thechloride is an alkyl chloride.

6. As a composition of matter, a blend of mineral lubricating oil and1,2-polypropylene glycol polymeric material of lubricating oil viscosityin an amount, by volume, of about one-fourth to about four-fold theamount of said mineral oil, said blend containing in addition a minoramount, suflicient substantially to lower the miscibility temperature ofsaid blend of at least one monohalide having at least three aliphaticcarbon atoms, said monohalide being selected from the group consistingof alkyl, alkaryl, arylalkyl and alioyclic monohalides, said monohalidebeing free of polar substituents and being soluble in said blend at themiscibility temperature of said blend.

7. Composition substantially as described in claim 6, wherein the1,2-polypropylene glycol material has at least one terminal groupselected from the class consisting of ether and ester groups.

8. Composition substantially as described in claim 7, wherein the1,2-polypropylene glycol polymeric material has a terminal ether group.

9. Composition substantially as described in claim 8 wherein themonohalide is an alkyl chloride.

10. Composition substantially as described in claim 8 wherein themonohalide is an arylalkyl chloride.

11. Composition substantially as described in claim 8 wherein themonohalide is an alkaryl chloride.

12. Composition substantially as described in claim 8 wherein themonohalide is an alioyclic chloride.

13. Composition substantially as described in claim 9 wherein the alkylchloride is isoamyl chloride.

WILLIAM T. STEvVART. ALFRED GOLDSCHMIDT.

REFERENCES CHTED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,481,278 Ballard et al Sept. 6,1949 2,510,540 Ballard et al June 6, 1950 2,520,733 Morris et a1 Aug.29, 1950 2,543,735 Stewart et al. Feb. 27, 1951 OTHER REFERENCES UconFluids and Lubricants, Carbide and Carbon Chem. Corp., New York, N. Y.,May 31, 1948, pgs. 14 and 15.

1. LUBIRCATING OIL COMPOSITION COMPRISING A MAJOR PROPORTION OF A BLENDOF HYDROCARBON OIL AND POLYALKYLENE GLYCOL POLYMERIC MATERIAL OFLUBRICATING OIL VISCOSITY IN AN AMOUNT, BY VOLUME, OF ABOUT ONE-FOURTHTO ABOUT FOUR-FOLD THE AMOUNT OF SAID HYDROCARBON OIL, AND A MINORAMOUNT, SUFFICIENT SUBSTANTIALLY TO LOWER THE MISCIBILITY TEMPERATURE OFSAID BLEND, OF AT LEAST ONE MONOHALIDE HAVING AT LEAST THREE ALIPHATICCARBON ATOMS, SAID MONOHALIDE BEING SELECTED FROM THE GROUP CONSISTINGOF ALKYL, ALKARYL, ARYLALKYL AND ALICYCLIC MONOHALIDES, SAID MONOHALIDEBEING FREE OF POLAR SUBSTITUENTS, AND BEING SOLUBLE IN SAID BLEND AT THEMISCIBILITY TEMPERATURE OF SAID BLEND.